lowcostdolly: I think you make an excellent point.
I confess that I am one of those passengers who really isn't interested in buying anything onboard, but I am always interested in an announcement from the flight deck and I always watch the safety demonstration.
It strikes me that on EZY and FR there are too many non-safety/operational PAs. I was led to believe that one of the reasons the captain makes a pre-flight announcement is so that passengers stand a better chance of recognising his/her voice in the event of an emergency. But unless you are alert, it can be difficult to distinguish all the automated/sales announcements from the captain's PA.
I have two suggestions:
1) make safety/operational PAs at a substantially higher volume so everyone can hear (it's been said before on here how frustrating it is when we can't hear you even when we want to!);
2) introduce these announcements with "This is a safety-related announcement" or similar wording to get people listening.
In my experience, the flights where passengers take the safety demo more seriously are those where the captain has emphasised - sometimes fairly firmly! - its importance.
Nick